It is very difficult to precisely center a centrally bored, rotatable object upon a mounting shaft or arbor. In the case of grinding wheels, diamond dressing rolls and the like type of rotary, roughly cylindrically-shaped articles, it is necessary to precisely align the bore axis of the object with the arbor or shaft upon which it is carried. Misalignment or cocking of the article relative to the shaft, such as on the order of thousandths, or sometimes, even tenths of thousandths, of an inch, are undesirable for many industrial purposes.
To center a bore upon its mounting shaft, it was necessary to precisely machine the bore and the shaft so that they precisely interfit. This requires precision roundness of the bore and the shaft circumference, precision straightness, etc. Even then, some misalignment is inherent because there is inevitably some manufacturing tolerance required, or inaccuracies which occur during machining operations, and there must be sufficient difference in diameters of the bore and the shaft so that the shaft can be slid into the bore. Hence, the shaft must be undersized at least sufficiently for telescoping it into the bore. This, of course, creates inaccurate centering in the cases of precision centering requirements.
The term "precision" centering, may, of course, cover a wide range of inaccuracies. Thus, for the purposes of this disclosure, an example may be in the range of 0.001 inch or less and preferably in the 0.00001 inches range.
Significantly, there has been a long standing industrial need for inexpensive systems for self-centering, precision centered bores on precision shafts. The invention herein relates to an improved system for accomplishing precision centering while simultaneously eliminating the need for precision finishing of the bore itself.